In the related art, an analog electronic timepiece has been used in which a motor drive device rotatably drives an indicating hand such as an hour hand and a minute hand. The motor drive device has a stepping motor for rotatably driving the indicating hand and driving means for rotatably driving the stepping motor.
The stepping motor has a stator which has a positioning portion (inner notch) for determining a stopping position of a rotor accommodating hole and a rotor, the rotor which is rotatably arranged inside the rotor accommodating hole, and a coil which is disposed in the stator.
A configuration is adopted in which drive pulses having different polarities are alternately supplied from a drive circuit to the coil so as to cause the stator to alternately generate magnetic leakage fluxes having different polarities. In this manner, the stepping motor, that is, the rotor is rotated by every angle of 180 degrees in a predetermined one direction (forward direction), and the rotor is stopped at a position corresponding to the positioning portion.
In general, in order to easily obtain the magnetic leakage flux for rotating the rotor, an integrated stator is used which has a narrow portion whose width is narrowed at two locations (apart from each other by an angle of 180 degrees) around the rotor accommodating hole formed to arrange the rotor so that the narrowed portion is easily saturated with magnetic flux.
As a technique used in order to easily obtain the magnetic leakage flux for driving the rotor, a so-called dually integrated stator is known. In the dually integrated stator, the stator is first cut and divided into two portions at two locations (apart from each other by an angle of 180 degrees) around the rotor accommodating hole so as to minimize a cross-sectional area of a magnetic path. The cut portion is welded and joined after a slit material formed of a low magnetic permeability material or a non-magnetic material is inserted into the cut portion so as to decrease magnetic permeability of the narrow portion (refer to JP-B-5-56109).